Current concepts in contact dermatitis

Assessment of potency of allergenic activity of low molecular weight compounds based on IL-1alpha and IL-18 production by a murine and human keratinocyte cell line

Assessment of allergenic potency of low molecular weight compounds is generally performed using animal models, such as the guinea pig maximisation test and the murine local lymph node assay (LLNA). Progress in unravelling the mechanisms of skin sensitisation, including effects on the production of cytokines by the different cell types of the skin, provides us with the opportunity to develop in vitro tests as an alternative to in vivo sensitisation testing. The aim of the present study was to establish an in vitro method to assess the potency of allergens, on the basis of their induction of cytokine production by murine and human keratinocytes. In the present study we used test systems comprised of the murine epidermal keratinocyte cell line HEL-30 and the human keratinocyte cell line HaCaT. We exposed these cell lines to the allergens ethyl-p-aminobenzoate (benzocaine), diethylamine (DEA), 2,4-dinitrochlorobenzene (DNCB), and phthalic anhydride (PA). IL-1alpha and IL-18 dose-response data were evaluated by non-linear regression analysis and at a stimulation index of 3 of cytokine production of treatment versus control, the corresponding allergen concentration was calculated. For HEL-30, for both cytokines DNCB showed the strongest potency followed in this order by PA, benzocaine, and DEA. This classification was similar to our previous findings obtained in the LLNA. For HaCaT, unfortunately, such ranking proved to be much less feasible. In conclusion, to assess the potency of allergens the murine keratinocyte cell line HEL-30 may be a useful in vitro test system, alternative to in vivo models, although this requires further testing using a much wider range of compounds.

11. Allergic and immunologic diseases of the skin

Many skin diseases have an inflammatory or immune component, and anti-inflammatory drugs comprise a major portion of a dermatologist's therapeutic armamentarium. Although causes of most of these diseases remain obscure, mechanisms of lesion formation and explanations for symptoms are increasingly well documented. These developments, coupled with the expected availability of novel selective immunomodulatory agents, herald a new era for immunodermatology. Patients with psoriasis, allergic contact dermatitis, atopic dermatitis, urticaria, and autoantibody-mediated blistering diseases are among those who are likely to benefit from advances in the understanding of disease pathogenesis and the emergence of immunotherapeutics.

New diagnostic classification of allergic skin disorders

PURPOSE OF REVIEW

To highlight the importance of one common nomenclature for allergic skin disorders.

RECENT FINDINGS

Diseases are best defined on the pathophysiological mechanisms underlying the symptoms. Although the mechanisms behind what is sometimes unfortunately referred to as 'atopic eczema' or 'atopic dermatitis' have been quite well understood for 30 years the present terms used are confusing. Over the years more than 20 different names have been used.

SUMMARY

Doctors, scientists and patients in the field of allergy must use one and the same terminology for allergic diseases or the result will be confusion. Diagnosis, prevention, treatment, patient advice, environmental relations, and the search for genetic markers are examples of areas that will be hampered by conflicting results. Strong efforts should be invested into broadly implementing the European Academy of Allergology and Clinical Immunology (EAACI) revised nomenclature for allergy.